Improvement in burglar-alarms



UNITED STATES PATENT OrrroE EUGENE LINNAED, or rEILADELrHIA, PENNSYLVANIA.

IMPROVEMENT IN BURGvLAR-ALARWIS.

Specification forming part of Letters Patent No. 175,612, datedApril 4, 1876; application filed March 20, 1876.

To all whom it may concern Beit known that I, EUGENE LINNARD, of tho city and county of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in Burglar-Alarms', and I do hereby declare the following to be a clear and exact description of the nature thereof, sufcient to enable others skilled in the art to which my invention appertains to fully understand, make, and use the same, reference being had to the accompanying drawings, making part-of this specification, in which- Figure l is a face view of the device embodying my invention. Fig.` 2 isla longitudi-v nal vertical section thereof. Fig. 3 is a similar view, showing the alarm operated.

Similar letters of reference indicate corresponding parts in the several figures.

My invention consists of a fastening of the order known as a chain-bolt, in combination with an alarm whereby, when attempts are made to open the door, shutter, or window, the alarm will be sounded, and the door or otherwise cannot be opened from the outside, and the burglar cannot silence the alarm or enter the room. For this purpose there is located in relation to the slotted platerof the fastening an arm which, when the bolt or button of the fastening is moved by attempts to open the-door or otherwise from without, and it thus presses the arm, causes the stop-bar of the alarm-hammer to be released, so that the alarm will be sounded, after which the Valarm can only be silenced by restoring the bolt to its normal position by operation from the inside of the room, the bolt then moving from contact with the aforesaid arm.

Referring to the drawings, 'A represents the casing or box of an alarm, in which, by certain clockwork or equivalent mechanism, the hammer B is caused to strike the gong or bell C. Secured to the casing is the slotted plate D of the fastening known as a chain-bolt, the button-or bolt E of which is connected by a chain, F, applied and operating as is well known. Within the casing there is mounted an arm, Gr, which extends under the slotted plate vD in the longitudinal direction thereof, and it is held in an elevated position by a spring, H, suitably arranged. To the axial rod a is attached an arm, J, which is connected by an arm, b, to a rotating disk or arm, K, pivoted to the casing A,- and to said disk or arm there is secured a-stop-bar or arm, L, which is arranged in proximity to the hammer B, so as .to come in contact therewith at the proper moment. The winding-post c of the clock-work or mechanism may project, so as to receive the winding-key, through the slot of the plate D, and the disk or arm K will have a suitable stop in order to limit the motions thereof.

-Theoperation is as follows: The casing A and chain F will be connected to the door or window and frame thereof, or parts of the shutter, or otherwise, so that the slotted plate and cha-in, when connected, will secure the door, or otherwise, in a nner similar to a chain-bolt, which permits the door, or otherwise,'to be opened to a limited extent, as is well known. y

The invention will here be described as applied to a door. y

When an attempt is made to open the door the button or bolt E will be drawn by the chain and moved in the slot of the plate D, and it thus depresses the arm G, as in Fig. 3. This operates the arm J, and causes the rotation ofthe disk or arm K, whereby the bar or Y lcontinue to be sounded, so-that there will scarcely be a failure of notification to the occupants ofthe room of the attempted entrance.

The alarm can only be stopped by closing the door and moving the button to its normal position shown in Figs. l and 2, and this can only be accomplished from the inside of the apartment. In this case the spring H elevates the arm G, and, by means of the intermediate mechanism, the stop-bar L is brought in contact with the hammer B.

It will thus be seen that if there is an attempt to open the door the alarm will bev sounded, the door cannot be opened to any material extent, and, owing to the chain-bolt, l the arm G, operating the stop-bar L of the the alarm emi. only be silenced by operation 1 alarm-hammer B, substantially as 'and for the of said bolt from the inside of the room. purpose set forth.

Having thus described my invention, what I claim as new and desire to secure by Letters Witnesses:

EUGENE LINNARD.

Patent, isn JOHN A. WIEDERSHEIM,

The chain-bolt D E 11", in combination With JAMES LINNARD. 

